Method of identifying precious stones



Jam 29, 1929.

F. HEITZLER METHOD OF IDENTIFYING PRECIOUS STONES Filed April 28, 1927 i lllllllll l 45 the stone is usually Patented Jan. 29, 1929.

FRANK HEITZLER, OI IBOSTON, MASSACHUSETTS.

mn'rnon or IDENTIFYING rnncrous sronEs.

Application filed April 28, 1927. Serial 110. 187,211. 7

This invention pertains to a method'of identifying precious stones, particularly those of a transparent nature. One of the greatest difficulties incident to the recovery of precious stones which have been lost or stolen is positive identification of such stones. This is due first to the fact that aside from weight and style of out, which of course are characteristics common to many stones of a given 10 kind, the only identifying features usually available are color, and water or brilliancy. Since there is seldom any fixed standard of color available with which a given stone may be compared to facilitate identification and since the brilliancy of a stone is apurely relative term, it is often very diiiicult, if not impossible, to make any positive identification of the stone which is suspected of having been stolen.

. It has long been recognized that most precious stones of natural origin have certain distinct characteristics when examined microscopically, for example, imperfections or abnormal peculiarities in cutting but more par ticularly interruptions of their optical homogeneity, all of such distinct peculiarities being hereinafter referred to for convenience as defects. These defects may consist. for

example, of irregularities in cutting, as above noted, but more es ecially such interruptions oftheir optical omogeneity as incipient fractures and 1m erfections 1n crystallization; included bub les of air or gases; specks or flakes of metallic oxides, or other opaque matter; and in the'case of diamonds, small particles of unc'rystallized carbon which appear" as black spots. It is very rare indeed that a stone, particularly a diamond, is found which does not have one or more of these 40 defects, and it is most unusual to find a stone of any size which does not contain several such defects, often 'of different kinds. Of course, if these defects are of great size, they may detract from the value of the stone, but

standing that the optical peculiarities thus Q6 referred to need not necessarily be of a chargraphs. After such a photo-micrograph has graph may be filed away in any custody, for example, by the sol e so cut as to avoid so far stone, by the purchaser or, by the insurance too 'as possible the large defects, and the remainacter such as to decrease the value of the stone.

As the inclusion of these defects is entirely fortuitous, it is substantially impossible or at least highly improbable. that any two stones will be found containing the same defects in the same relative positions, and thus were it possible to make note of the defects in a given stone and to keep a record of such defects, avery definite and accurate means of identification would be available.

As a usual thing precious stones employed for jewelry are quite small (a diamond of onequarter inch diameter being quite unusually large and most of them being much smaller than this) while the defects which must be relied upon for identification are of microscopic size and only visible through a microscope of high power. Furthermore, the'mere observation of these defects is not suflicient since it afiords no standard of com arison by means of which the stonemay be i entified at alater time.

In accordance with my present method I prepare a photo-micrograph, referably using a magnification of the or er of 250 diameters, although I do not wish to restrict myself to this articular magnification, it being possible t at good results may be secured with'either a higher or lower power. 35 In order to obtain desirable results and to I produce a photographic print which will be of any value for later comparison for identification purposes, I find it desirable to light the stone in such a manner and to employ lenses of such character as to reduce as far as possible contrasting effects in thenegative and print, this procedure bein quite contrary to the usual practice in maIrin'g photo-microbeen made and microscopically compared to the stone for its accuracy, such photo-microsuitable of the company. I further contemplate that this process may be applied upon the entry of the stone into this country and that the photo- P microg'raphic record thus made ma be kept at the customs house and that a duphcate may be furnished to each successive purchaser of the stone. Thus if at any subsequent time the stone should be stolen or lost such print or prin'tswould furnish an accurate and undeniable standard of comparison with which a no stone might be compared for identification purposes.

In making such comparison it would simply be necessary to take the photo-micrograph, supposed to corresnond to the suspected stone, and to examine the stone under microscopic power sufiicient to exhibit defects clearly. Preferabl the photo-micrographs should in each case hear, a legend showing the amount of magnification employed in making it, together with other data, for example, the distances of the various defects from a fixed datum point of the stone, and in addition the print may bear other data as is often furnished to the purchaser of a precious stone, for example, a statement of the weight, style of cutting, color, etc.

While the above system of identification thus briefly outlined appears quite simple (although I believe it to be novel), I have found through a long course of experiments that the production of satisfactory photo-micrographs'of precious stones, and particularly diamonds, is not at all easy if such photomicrographs are to form reliable standards of comparison, as above described. In the first place the irregular surface presented by the facets of the cut stone, and in the case of a diamond particularly the fact of its double refractive properties, makes it exceedingly difiicult to produce a photo-micrograph clearly disclosing the depths of the stone throughout its entire area. In the second place the defects which occur in such a stone do not necessarily liein a single plane parallel to the plane of the photograph but in fact usually occur in planes spaced from one another throughout the depth of the stone.

Lenses used for photo-micrography arc necessarily of such character that the depth of focus is exceedingly short in order to obtain the desired clearness of definition, it being a well known principle of optics that any attempt at increase in depth of focus necessarily results in reducing definition. Thus in order to focus sharply upon a defect which occurs, for example, near the top or front face of the stone, the lens will not produce a sharp image (and often forms no image at all) of defects lying but a short distance, for example one half of a millimeter, below or behind the plane of the selected defect. Thus if, for example, a large stone having a defect near its front surface were photographed for identification purposes and the lens were so focused I as to show this defect at the front of the stone, it would fail to show other defects, so that this single defect would ordinarily constitute the only means of identification. While this might be of some utility, it is not all that could be desired since there is at least a very remote possibility that two stones might be found having a single defect of substantially the same shape and kind and in the of the stone and lens so as same location. It is thus desirable in order that the process may be of real commercial value that the photo-micrograph show substantially all or at least several of the defects in the stone. Accordingly my preferred method consists in making such photo-micrographs in which defects occurring at different planes of the stone are shown upon the same print and with substantially the same sharpness of definition.

To accomplish this result I prefer to employ apparatus such as is more fully disclosed in my copending application Serial No. 187,212 filed April 28, 1927. By means of this apparatus I first examine the stone microscopically to determine defects lying for example ator near the front or top surface of the stone. I then vary the relative position to focus upon a plane of thestone which is deeper within the latter and then again examine the stone for defects at this plane. I may thus'continue with a series of settings of the lens until I have determined with accuracy those planes in which substantial defects are to be found, noting and recording the position of each such plane. I then expose a photographic plate to a magnified image of the stone, such image being that of the first plane in which a defect was found. After exposing the plate find that it shows substantialpreviously found by 1y all of the defects occurring throughout the depth of the stone, clearly and with sharp definition and in their proper relative positions. This negative may be used to make suitable prints, and since as above described it is seldom that the stone does not exhibit more than one defect, such a print, showing all of the defects in one view, is exceedingly valuable as a means of identification of the stone since the various defects occurring in the stone are usually of distinctive shape and are at definite distances from some fixed datum point, for example, the front surface of the stone. Oftentimes the defects, for example, cracks or flaws, are of curious and grotesque outline while the spots or specks of carbon usually occur in flocks or grou s in the same time, but except in unusual cases I prefer the first procedure as more simple and accurate. 7

While my method may undoubtedly be carried into effect in various ways it is essential from the commercial standpoint that it be capable of use by relatively unskilled persons and that it be possible to prepare composite photo-micrographs quickly at relatively low cost. With these objects in View I have designed the apparatus shown in the accompanying drawings, such apparatus being highly effective for the purpose and wholly practical from the commercial standpoint, although I wish it to be understood that the apparatus disclosed is merely illustrative of various devices which undoubtedly may be employed for carrying the process into effect.

In the accompanying drawings Fig. 1 is a plan view of suitable apparatus for use in practicing the method herein disclosed;

Fig. 2 is a side elevation partly in section of the same apparatus;

Fig. 3 is a rear elevation of a device for holding unmounted stones in proper relation to the axis of the photographic lenses;

Fig. 4 is a section, to larger scale, on the line l l of Fig. 3, showing an unmounted stone held in position for photography;

Fig. 5 is a front elevation illustrating the focusing screen or ground glass of the camera as provided with centering graduations;

Fig. 6 is a diagrammatic side elevation of an unmounted stone showing defects at dif ferent distances from its front face;

Fig. 7 is a view, to larger scale, illustrating the appearance of the magnified image of a stone upon the focusing screen of the camera showing defects occurring, for example, in the plane 88 of Fig. 6; and

Fig. 8 is a view showing the general appearance of a photo-micrographic print made in accordance with the present method and showing defects in the planes 88 and 9-9 of the stone of Fig. 6. together with a suitable descriptive legend.

WVhile my novel method may doubtless be carried out by the use of other means than that herein disclosed, I have found the up paratus illustrated in the accompanying drawings to be very satisfactory for the purpose and to give excellent results. This apparatus comprises an elongate base or bed 1 which may be made of .vood. metal or other suitable material and which supports the camera, the means forholding and lighting the stone, and other I accessories described hereinafter more fully. Preferably the camera is mounted upon one end of this base or bed 1 and comprises the backboard 2 connected by the bellows 3 to the front or lens board t. The front board 4 is mounted upon a support sliding on or in suitable guides extending longitudinally of the base 1 and this by means of the set screw 1.

and is connected to the reduction gearing,

such shaft 9 preferably extending to a point adjacent to the backboard 2 of the camera and being furnished with a knurled knob or disk 10 by means of which the shaft may be turned. By turning this shaft the front or lens board of the camera may be moved very slowly and with great accuracy.

The front board 4 is preferably provided with a laterally extending bracket arm 11 which normally engages a sliding actuator bar 12 of a nucrometer indicator 13. This micrometer indicator may be of any usual type, preferably reading to one hundredths of a millimeter, and is furnished with an index needle let cooperating with a scale 15. Preferably the scale is carried by a movable ring 'so that the zero point of the scale may be adjusted. This type of micrometer indicator is old and well known and in itself forms no part of the present invention. Preferably this indicator is bodily adjustablelongitudinally of the bed 1 but is normally fixed in position. As one convenient means of mounting the indicator, I fix a rod. 17 by means of brackets 18 to the edge of the bed 1, the rod being spaced from the bed, and by means of any suitable clamp (not shown) secure the indicator to the rod.

The lamp 19 is mounted on a standard 90, preferably adjustably secured to the bed. 1 and the lamp may be provided with reflectors and with condensing lenses in a telescopic casing 21 so as to throw a parallel beam of light along the axis of the camera lens.

The holder for the stone to be photographed preferably comprises a base plate 22 adjustable longitudinally of the bed and which may be secured in adjusted position Zlhis plate 22 carries a sccondplate 22'having a transverse slot 22* for the reception of "aching screw 22. The plate 22 is thus ad ustable transversely of the bed 1 with 22. The plate 22" car ti al standard compris the lower portion 23 and the upper portion 2;, said upper and lower portions being united by hinge 525i permitting the upper portion, when desired,

to be swung downward into a substantiady horizontal posit-ion. In order to hold the upper part 24; of the standard in vertical alignment with the lower portion, I provide a pair of spaced ears or brackets 26 projection Ian!

ing from the art 24 and a lower ear of bracket 26" Pro ecting from the part 23, the bracket 26 normally fitting between the brackets 26. The several brackets are furnished with aligned openings for the reception of a locking pin 27 which normally extends through the openings and thus holds the parts 23 and 24 in rigidly aligned position.

The upper part 24 of the standard comprises a disk-like portion 28 of annular form and this disk is provided with a rim-like flange 29 forming a retainer for cam disk 30 which is disposed against the rear face of the disk 28. This cam disk 30 is free to rotate relatively to the disk 28 and I provide a handle 31 for turning the cam disk.

The cam disk 30 is furnished with a plurality of cam slots 32, four such slots being shown herein. Each of the cam slots 32, receives a rearwardly directed pin 33" carried by a corresponding holder bar 34. These bars 34 are preferably disposed radially with respect to the center of the disk 28 and slide in suitable guideways in or carried by the disk 28. Preferably these holders 34 are urged inwardly means of springs (not shown) and their inner ends project into the central opening or aperture 35 in the disk 28. By actuation of the handle 31, the cam disk30 is rotated and by means of the cam slots 32, acting upon the pins 33, the several holder bars 34 are simultaneously retracted, thus leaving a space between their inner ends for the reception of a stone 36. The inner ends of the bars 30 are of substantial thickness so as to provide broad surfaces for engagement with .the edges of the stone, thus preventing the stone from tilting or tipping after the several bars have been brought into contact with it.

In order to facilitate the location of the stone between the ends of the holder bars and to make certain that the front face of the stone lies perpendicular to the axis of the lens, I provide a cover plate 38 (Fig. 4) having a handle 39, said plate being adapted to engage the front face of the disk 28. To hold this cover plate temporarily in position I provide a pair of pins 37 projecting forwardly from the disk 28, such pins preferabl having enlarged heads adapted to overlie the forward surface of the coverplate 38. The pins 37 are spaced apart adistance slightly less than the diameter of the cover;

plate 38 so that it is possibleto push said cover plate edgewisc between the pins until it jams and is thus frictionally held.

"The backboard 2 .of the camera carries the focusing screen 42 (Fig. 5) which may be of ground glass as is usual, but I preferably provide this screen with a graduated scale or scales 43 in which the aduations preferably extend in opposite 'rections from a zero point at the center, such zero point lying upon the optical axis of the lens.

If desired I may interpose a diaphragm 85 either between the lamp 19 and the holder for the stone, or between the holder and the camera lens, such diaphragm being provided with an aperture which may be adjustable or not, as desired. Since such diaphragms are will known in the optical arts, it is unnecessary to describe this diaphragm in detail herein except to say that it may be mounted upon a standard 87 which, as more fully disclosed in my copending application Serial No. 187,212 filed April 28, 1927, may be fitted into a suitable socket. carried by the stone supporting standard, or which may have an nglividual foot adapted to be secured to the 'The operation of the above apparatus is substantially as follows, it being assumed that an unmounted stone is to be examined and photographed. The operator first applies the covcr plate 38 to the forward face of the stone supporting standard, temporarily retaining the cover plate in position by engagement with the pins 37. He then removes the locking pin 27 and swings the upper part of the standard down to a substan-' is now moved to retract the sliding holders- 34' and the stone to be dropped into the space b ends of the holders so that the table surface 41 of the stone rests upon the exposed upper surface 41 of the cover plate 38. The handle 31 is now released, permitting the holders 34 to move inwardly until their innerends engage the stone, thereby gripping and properly centering the latter. The upper part of the standard is now swung back to its normal position and locked by means of the pin 27 and the cover plate 38 is then grasped by means of its handle 39 and removed from between the pins 37, thus exposing the stone in properly centered position with its axis ephotographed is lens.

The lampis now lighted so as to throw a beam forwardly through-the stone, lighting the entire substance of the latter. The light, as above described, is controlled by means of suitable lenses and diaphragms so ween the innerion that it lights the stone uniformly but does I I not pass substantially beyond the lateral edges of the stone; 3

The operator now roughlyv adjusts the frontboard and lens 19 of his camera until he obtains an image of the. stone upon the ground glass and thenfurther carefully adjusts the lens by means of the fine racking mechanism 7, 8, 9 abovedescribed until a greatly magnified image of the front face i of the stone is brou ht into shar upon the ground gdass." By a standard 23 laterally the center of the image definition j usting the HO substantially in the axis of the photographic is hrought to the zero mark on the focusing screen scale and the diameter of the image is new preferably noted with reference to l scale and recorded. The operator now lies a magnifying glass of high power and examines the enlarged image or" the stone on the ground glass, searching for any detects which may lie closely adjacent to or upon the front face of the stone. If no such detects found in this front plane he moves the camera lens sli htly so as to focus upon a plane, for example, a plane one illimeter within the depth of the examines the stone at this cts and, assuming that he dist in this plane, he makes note and preferably sets the micromabove described so that it indicates crntact member 12 ot the gage beengagement with the arm 11. He also notes t is diameter of the image by relercnce to the scale on the ground glass and also notes and records the lateral position of the de ct or lJLi GCtS as indicated by the scale,

t thing record of these observations.

e operator new again adjusts the camera "ens focus upon a plane still deeper in the and it he discover detects in this plane, he notes "he reading of the micrometer gage i s him the depth of this secplane behind he first plane in which defects iscovered. He thus continues eX- o the stone in which discts occur and recording by refercrometer the location of each Zero micrometer po i by his original inspecoses this plate for the then, after closing the he again moves the lens until ws readingcorre- 7 plane in which deshutter is now opened second exposure made upon the same is osure imprintin upon ilate an im g'e of the second plane cts occur, such image being acis cred with the first image.

posures are enough. for practhe operator may continue exposures this plate (within 1' s capacity) corresponding to i i hich he has previously noted amerabefore each exhas been photographed to insure proper identification of the stone, the plate is removed, developed and fixed in the usual way and employed in making prints. These prints as above described show the various defects existing in the stone in their relative lateral positions andin their proper and peculiar shapes and groupings. For example, if the first plane of the stone in which a defect is found to occur isthe plane 8--8 of Fig, 7, the first image which is photographed may have the appearance of that shown in Fig. 8 wherein the defects D consisting of groups of minute carbon specks, are clearly and definitely shown andtheir relative lateral positions and distances from the center of the image may readily be noted. Considering now that the stone shown in Fig. 7 contains further defects D in the plane 9--9 and that the second exposure of the plate is to the enlarged image of this plane of the stone, the photographic print, when finally developed, will have the appearance shown in Fig. 9

wherein not only the defects D found in the plane 8-8 are shown but also the defects D occurring in the plane 9-9. This print also is preferably provided with certain data for use in subsequent comparison, such data comprising, for example, a statement of the magnification employed in making the negative, the depth of the planes 8-8 and 9-9 behind the trout face 41 of the stone, the diameter of the image upon the ground glass and the distances of the defects D and D from the axis of the image.

it at any later time it be necessary to identify the stone it is merely suficient to mount the stone in an apparatus of the general type above described and to compare its image upon the camera screen with the image shown in the photograph, As the photo raph bears a legend, as above described, stating the sevthe defects which the photograph shows to I occur in each of these planes. vVhile the apparatus licreinabove described is convenient for this purpose it is not wholly necessary for examining the stones for identification purposes since a microscope of usual type might be employed or alternatively the image of the stone, might be thrown upon a large screen by means of stereopticon apparatus, or in fact any suitable means may be employed for producing the enlarged image. However, I find it advantageous to provide a portable viewing apparatus (not herein illus trated) which comprises an adjustable lens and a ground glass screen mounted in the op posite ends of an' adjustable holder consist ing, for example, of a pair of telescoping tubes. F or convenience such tubes may be relatively adjustable by means of a micrometer adjustment provided with a scale to indicate the relative movement of the screen and lens in examining different planes of the stone. As this apparatus forms no part of the present invention and is not claimed herein, further description is unnecessary.

If instead of an unmounted stone it be desired to examine a mounted stone, for example one held in a ring, an appropriately modified form of holder may be substituted tor that hereinabove described. In making photo-micrographs of mounted stones, it may be necessary to employ incident light, that is to say, light directed laterally or vertically upon the forward or side face of the stone, and While this arrangement of lighting may be necessary in certain cases, I prefer if possible to employ the lighting above more specifically described.

While I have described a certain series of steps in performing my method, together, with desirable apparatus for use in the practice of the same, I wish it to be understood that the method is not necessarily confined to this particular order of steps or to the Whole number of steps described, or to the apparatus herein illustrated, but that other and equiyalent steps may be substituted for those hereinabove described and that in some instances certain of the steps described may be omitted without departing from the spirit of the mvention. i

I claim:

1. That method of identifying transparent precious stones which comprises as steps projecting upon a screen a magnified image of that plane of the stone in which a defect occurs, measuring and recording the distance of the defect from a definite datum point of the image together with distinctive characteristics of the defect, and employing said record for subsequent identification of the stone.

2. That method of identifying transparent precious stones which comprises as steps projecting upon a screen a magnified image'of one plane of the stone in which a defect occurs, measuring and making a permanent record of the diameter of the image andthe disstance of the defect from a fixed datum point of the image, measuring and making a permanent record of the depth of the defect from the front face of the stone, and employing the records thus obtained for subsequent identification of the stone.

3. That method of identifying transparent precious stones which comprises as steps producing a magnified image of the stone at a plane in which a distinctive defect appears, recording identifying characteristics of said defect, producing a magnified image of the stone at another plane in which a distinctive defect appears,'recording identifying characteristics of said second defect, recording the distance between said planes, and employing the record thus obtained for subsequent identification of the stone.

4. That method of identifying transparent measuring and making a permanent record of the diameter of the image and the distance of the defect from a selected definite point of the image, projecting upon the screen a magnified image of a second plane of the stone in which a defect occurs, measuring and making a permanent record of the diameter of said second image and the distance of the defect from a selected definite point of the image, and employing said records for subsequent identification of the stone.

5. That method of identifying transparent precious stones which comprises as steps focusing a camera lens upon a plane of the stone in Which a defect occurs, accurately measuring the distance between said defect and a fixed datum point of the stone, making a photo-micrographic print shoWi'ng such defeet, and employing such print for subsequent comparison in identifying the stone.

6. That method of identifying transparent precious stones which comprises examining the stone microscopically to discover defects therein, accurately determining the plane, with reference to a fixed datum point of the stone, at which such a defect occurs, making record of the distance between said plane and datum point, preparing a photo-micrograph showing the defects at said plane, and employing such photo-micrograph for subsequent comparison in identifying the stone.

7. That method of identifying transparent precious stones which comprises making a .photo-micrographic record of a plurality of distinctive defects in a stone, measuring and recording the distance between said defects and a fixed'datum point of the stone, and cmploying said record for subsequent identification of the stone.

8. That method of identifying transparent precious stones having internal defects there in which comprises as steps accurately measuring and making record of the relative locations of at least two defects within the substance of the stone, photographicaily recording the appearance of said defects, and employing the records in subsequent identification of the stone.

I 9. That method of identifying transparent precious stones which comprises as steps microscopically examining the stone in a plurality of parallel planes, carefully measuring the distance of each plane in which distinctive defects occur from a fixed datum point of the stone, making record of such measurements, photo-micrographically recording the defects in at least two of said planes, andemploying such photo-micrographic record for subsequent identification of the stone.

10. That method of identifying transpar ent prec ous stones which comprises as steps nicromcter measurement the a two planes of the stone in defect occurs, making a record and a photo-micrograph of 'ects, and employing this recioto-micrographic representa Qefects for subsequent identificamethod of identifying transparones which comprises as steps photo-micrographic record of a of defects in the stone together record of the distance, along an optiof the stone, bet-ween the planes in i such defects occur, and employing record for subsequent identification of last method of identifying transparcious stones which comprises as steps tag the stone before a photo-microiic camera lens, adjusting the lens by as of focusing screen until the screen an image of the stone in which defects sharply defined, making permanent of the exactsetting of the lens, makanicrograph of the stone with determined adjustment of the lens, 1 F g this photoanicrograph and .ens setting for subsequent comso '11 identifying the stone.

method of identifying transparec1oustones which comprises as steps e 'ng the stone before a phto-micro- .c camera lens, adjusting the lens by n1 I a focusing screen until a sharply a of the front face of the stone i the screen, accurately deterecording the position of the justing the lens until the he s image of a plane of the stone -.fect occurs, accurately deteracording the position of the lens a ring a photo-micrograph of the lens in its latter position and employing the photo- I. id the recorded measurements for subsequent comparison in one.

hllOCl of identifying transparnes which comprises as steps crding upon the same photographic plate magnified ii ages of at least two planes of a stone in which defects occur, developing and fixing the plate to provide a permanent record of such defects, and subscqucntly forming magnified images of the stone and comparing such images with the photographic record. for identification purposes.

15. That method of identifying transparent precious stones which comprises as steps determining the relative location of a plurality of parallel planes of the stone in each of which a defect occurs, successively exposing a photographic plate to a magnified image of each of said predetermined planes of the stone, developing and fixing the plate, and employing the permanent record thus obtained for identification of the stone.

16. That method of identifying transparent precious stones which comprises as steps microscopically examining a stone and recording the distance from a fixed datum point of each of at least two parallel planes in which defects occur, exposing a photographic plate successively to the magnified images of each of said planes, developing and fixing the plate, making a photographic print from said. plate, and providing the print with a legend indicative of said recorded distances.

17. That method of identifying transparent precious stones which comprises as steps successively projecting upon a screen magnified images of two planes of the stone in each of which a defect occurs, measuring and recording the distance between said planes, measuring and recording the diameter of each image and the distance of a defect from a fixed datum point of each image, photographically impressing each of said images in superposed registered relation upon the same plate, developing and fixing the plate, making a print from the plate, providing the print with a legend giving the measurements recorded, and subsequently forming magnified images of the stone and comparing such images with said print for-identification purposes.

Signed by me at Boston, Massachusetts, this th day of April, 1927.

FRANK I-IEITZLER. 

